Air pollution in Nairobi is likely to become significantly worse by 2030 – putting thousands of lives at risk from one of the biggest killers in urban Africa – unless action is taken now, according to an alliance of African and British experts.

Researchers at the University of Birmingham have discovered that the mass extinction seen in plant species caused by the onset of a drier climate 307 million years ago led to extinctions of some groups of tetrapods, the first vertebrates to live on land, but allowed others to expand across the globe.